Wagons - Dynamic behaviour of coupled bogie-wagon units fitted with draw bars

The in-service behaviour of coupled wagon units linked by means of draw bars has also been studied in the project entitled “Defining test conditions for draw bars” in order to establish a test method for draw bars and the requisite test conditions. To this end, numerical simulation has determined the permitted longitudinal compressive forces (LCFs) for a coupled wagon unit in an S-curve of radius 150 m and a straight transition section of 6 m. The minimum LCF values permitted in full curves and S curves have also been defined for various coupling configurations (screw coupling, diagonal buffers and draw bar).

It was finally concluded that it is possible to determine the permitted LCFs for two-axled wagons and two-bogie wagons. Coupled wagon units linked by means of a draw bar with stabilising articulation can thus tolerate substantially higher LCFs than a standard coupling. However, coupled wagon units linked via a draw bar without stabilising articulation can tolerate lower LCFs than standard couplings.

The simulations conducted showed that, given the difference in permitted LCFs between standard couplings and coupled units linked via draw bars with stabilising articulation, coupled units of bogie wagons can be exempted from propelling tests.